Wood-preserving composition



20 by these solutions.

Patented Feb. 8, i927.

rnmnmcnfnasonlo; or LUDWIGSHAFEN-ON-THE-RHINE, GERMANY.

' woon rmisnnvmo' oomrosrrron.

no Application illed May a m- 1925, Serial 1110. 31,696, and in Germany February 13, v1925.

For many years dinitro-phenol and dinitro-cresol have been applied .with good re'- to the preservation of wood, either in the nascent state orin the form of alkalineor aniline salt (German ,Generally these nitro-eombinations are applied in mixtures with large quantities of sodium fluoride.

But is has been proved, that these solutions strongly affect the vessels for holding the.

impregnation liquid. To prevent this inconvenience, additions .to' the preserving composition have been proposed, for instanoe, the

addition of potassium bichromate (German Patent 299,411 or the addition of compounds of the 'i-valent metals, particularly of zinc (German Patent 368,490) Recently the application of antimonial salts hasbeen recommended to prevent the attack upon iron But the opinions concerning the advantages of such additions are b nomeans agreed; it is said-that an additlon of bichromate for example favours the action upon the iron. p p I have disoovered that aqueous solutions of sodium fluoride and dinitrophenol or dinitrocresol, which strongly afieot iron not only in the cold state, but m a still higher degree in a heated state, immediately lose this prop- Patent 219,893)

erty, if a small quantity of water-glass is added. But this favorable'result can not be explained by supposing, that the alkaline strength of water-glass saturates the dinitrophenol to dinitrosodium phenolate, since an equivalent quantity of dinitrosodium phe-'85 nolate in the mixture for impregnation does not show in the'least de ree the same favor- Y able pro erties.. There ore, there is an effeet, Wh10h is specific to the potassium'or. sodium silicate. 40

Example.

88 parts sodium fluoride, 10 parts dinitro cresol, and 2. parts water-glass, finely powdered, are mixed together. easily and completely dissolved in water; the solution does not attack iron even in the heated state,

I claim as my invention:

A wood-perserving composition consist- O 5 ,mg of 88 7 parts, by wei ht, of sodium-fluoride; 10 parts, by weig t, ofdinitro-orthocresol; sand 2 to 10 parts, by weight, of water-glass. I

In testimony whereof I have aflixed my signature. I

- FBIEDBICH-RASOHIG.

The mixture is 

